/*
* Search the dentry child list for the specified parent,
* and move any unused dentries to the end of the unused
* list for prune_dcache(). We descend to the next level
* whenever the d_subdirs list is non-empty and continue
* searching.
*/
static int select_parent(struct dentry * parent)
{
struct dentry *this_parent = parent;
struct list_head *next;
int found = 0;
DEFINE_LOCK_COUNT();
spin_lock(&dcache_lock);
repeat:
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
if (!atomic_read(&dentry->d_count)) {
list_del(&dentry->d_lru);
list_add(&dentry->d_lru, dentry_unused.prev);
found++;
}
if (TEST_LOCK_COUNT(500) && found > 10) {
debug_lock_break(1);
if (conditional_schedule_needed())
goto out;
RESET_LOCK_COUNT();
}
/*
* Descend a level if the d_subdirs list is non-empty.
*/
if (!list_empty(&dentry->d_subdirs)) {
this_parent = dentry;
#ifdef DCACHE_DEBUG
printk(KERN_DEBUG "select_parent: descending to %s/%s, found=%d\n",
dentry->d_parent->d_name.name, dentry->d_name.name, found);
#endif
goto repeat;
}
}
/*
* All done at this level ... ascend and resume the search.
*/
if (this_parent != parent) {
next = this_parent->d_child.next;
this_parent = this_parent->d_parent;
#ifdef DCACHE_DEBUG
printk(KERN_DEBUG "select_parent: ascending to %s/%s, found=%d\n",
this_parent->d_parent->d_name.name, this_parent->d_name.name, found);
#endif
goto resume;
}
out:
spin_unlock(&dcache_lock);
return found;
}
/* mm->page_table_lock is held. mmap_sem is not held */
static inline int swap_out_pmd(struct mm_struct * mm, struct vm_area_struct * vma, pmd_t *dir, unsigned long address, unsigned long end, int count, zone_t * classzone)
{
pte_t * pte;
unsigned long pmd_end;
DEFINE_LOCK_COUNT();
if (pmd_none(*dir))
return count;
if (pmd_bad(*dir)) {
pmd_ERROR(*dir);
pmd_clear(dir);
return count;
}
pte = pte_offset(dir, address);
pmd_end = (address + PMD_SIZE) & PMD_MASK;
if (end > pmd_end)
end = pmd_end;
do {
if (pte_present(*pte)) {
struct page *page = pte_page(*pte);
if (VALID_PAGE(page) && !PageReserved(page)) {
count -= try_to_swap_out(mm, vma, address, pte, page, classzone);
if (!count) {
address += PAGE_SIZE;
break;
}
/* we reach this with a lock depth of 1 or 2 */
#if 0
if (TEST_LOCK_COUNT(4)) {
if (conditional_schedule_needed())
return count;
RESET_LOCK_COUNT();
}
#endif
}
}
address += PAGE_SIZE;
pte++;
} while (address && (address < end));
mm->swap_address = address;
return count;
}
void prune_dcache(int count)
{
DEFINE_LOCK_COUNT();
spin_lock(&dcache_lock);
redo:
for (;;) {
struct dentry *dentry;
struct list_head *tmp;
if (TEST_LOCK_COUNT(100)) {
RESET_LOCK_COUNT();
debug_lock_break(1);
if (conditional_schedule_needed()) {
break_spin_lock(&dcache_lock);
goto redo;
}
}
tmp = dentry_unused.prev;
if (tmp == &dentry_unused)
break;
list_del_init(tmp);
dentry = list_entry(tmp, struct dentry, d_lru);
/* If the dentry was recently referenced, don't free it. */
if (dentry->d_vfs_flags & DCACHE_REFERENCED) {
dentry->d_vfs_flags &= ~DCACHE_REFERENCED;
list_add(&dentry->d_lru, &dentry_unused);
continue;
}
dentry_stat.nr_unused--;
/* Unused dentry with a count? */
if (atomic_read(&dentry->d_count))
BUG();
prune_one_dentry(dentry);
if (!--count)
break;
}
spin_unlock(&dcache_lock);
}
